3.91 or 4.10 Ring and Pinion for 741 Case

I’m looking for a gear so my oldest brother can race my 72 at the Mopar nationals in August. We haven’t been since we were kids and decided that our summer vacation would be a trip to the nationals with him running my 72 Duster and me in the 71. I have the 741 with the 3.23 sg currently so if I can just change the ring and pinion it will be quite a bit of savings to me.